303 British question

[Bman1954]

I have a No.4 mk1 with a 2 groove barrel which slugs at .3145.I have a lyman 314299 mold which casts at .3155.i have tried different powders and gas checks to no avail.Everything I tried keyholes or shot all over the place.I Read on the forum about using cream of wheat filler.I tried that yesterday on top of 21 grains of IMR 4227.This combination shot several 3 inch groups at 100 yards.The bolt however is sticky on extraction.The primers look all right but I wonder if the pressure is too high. Craig

[1Shirt]

Suggest using COW only in straight walled cases. COW in bottle neck cases can increase pressure a great deal. Suggest you try Dacron fill ILO of COW. Good luck!
1shirt!

[Scharfschuetze]

NOE makes a 316299 mold that casts large enough for my Enfields with bores similar to yours. The long bore riding nose works well in two groove barrels such as yours.

Buckshot (member here) made me a very nice .317 sizer for my RCBS Lubrsizer.

You may need to get the above combination to really get your No 4 shooting well.

[curator]

COW works fine in the very tapered .303 British case provided you don't try to push the bullet too fast. 21 grains or 4227 is a bit too fast IMHO. 16 to 18 grains would probably give better accuracy and not be high pressure. I have found 4227 to be somewhat "quirky" when used as a cast boolit powder in military-type cartridges. Pressures go from moderate OK to very high very quickly. I much prefer SR4759, Reloder7, AA5744, IMR4198 or Aliant 2400 when using fillers in large volume cases for light loads. Here's an article written by one of us cast-boolit guys about .303 British and 2-groove barrels.:http://www.303british.com/id37.html

[mac1911]

I didnt have to much luck with my No4 MkII until this weekend.... raining ,cold , windy , dark day perfect for load testing done @ 50 yards from the lead slead plus rifle rest
I had a short stint with Trailboss before powder and primers vanished and Im just getting back to cast loads
I use the 314299 which drops just a touch over 314 by my calipers. Gas checked/lubed they come in at 206-210 grains
Trailboss was at starting load per TrailBoss instructions so so accuracy ok mouse farts for blasting soda bottle or milk jugs 40 yds max good for young ones to shoot from a big rifle
2400 a little better bit more mmpphh still plinking loads at best..... I think a higher powder charge might tighten things up
Then H4895 things got fun only wish I made more to try @ 100 yards of corse the sights need to be fine tuned, when I settle on a load

[longbow]

I have shot quite a number of NOE 316299's over 22 grs. IMR4227 with COW filler with no troubles at all. No flattened primers, no sticky bolt lift, good accuracy, complete powder burn... all good stuff.

I exchanged several e-mails with David Southall who wrote the article curator linked to. He was very helpful and I took his advice. So far, I have been very happy with filler loads. Yes, I believe they raise pressure but as long as it is within acceptable working pressures who cares? Actually raising the pressure with some powders is why I use the filler in the first place. Mostly I use it because I want 100% loading density and I mostly run PB boolits. Being lazy and cheap means I do not want to spend time and money on gas checks when I don't need to.

I have loaded and left rounds outside for 10 months through the winter and found no extra packing or solidification of those rounds compared to freshly loaded filler rounds, or differences in accuracy, or pressure signs.

Not sure I would use COW filler in a cartridge like 7mm mag, .264 Winchester, .243 or similar with large volume body, sharp shoulder and small neck. However, I also would not limit its use to straight walled cartridges either.

I see no caking, plugging, build up behind the neck or brass stretching using COW filler in my .303's.

Sorry, I shouldn't ramble on but I keep hearing all sorts of arguments against fillers and few for fillers. Like anything else, I think if they are used appropriately and responsibly the are another tool for reloaders to use. Let's not forget that putting too much powder in a cartridge can lead to high pressure too.

One does have to work up loads with filler included though. Don't just go dropping filler into a load because there is room in the cartridge, that could lead to high pressure and bad things. Start low and work up with filler included.

In my experience your 21 gr. load of IMR4227 with COW filler is perfectly safe. Might not be the most accurate load for your gun but it sounds like it is doing well regardless.

Are you full length sizing or just neck sizing? If just neck sizing maybe try annealing then full length sizing and fire forming to your chamber again then see if the bolt is still sticky.

Do the rounds chamber easily or do they drag on the case neck? Just thinking they might be a bit tight or maybe the chamber is a bit rough?

By the way, congratulations on owning a Lyman mould that casts oversize! My 314299 cast at 0.312" with range scrap or wheelweights so it got lapped out but then I messed it up when I decided to remove gas check shanks. I subsequently bought an NOE 316299 that casts 0.315"+ with range scrap or wheelweights. I am very happy with my NOE mould.

Longbow

[DougStump]

Bman1954,

I've had good luck with the Lee 155 & 185 grain. If you PM me your snail mail address I can send you some to try. I know I have some 155's on hand, not sure on the 185's but I'll look.

[1johnlb]

Keyholing comes from one of two things 1] undersized boolit, 2] soft alloy for the psi. I don't have a 2 groove but from my understanding they have bores that run .316-.321. Slug your barrel.

[303Guy]

They also have a simple taper throat of about 1½° included. That taper starts at the throat entry and the rifling begins somewhat in.

I've found the two narrow grooves don't hold the boolit well if the allow is too soft or the pressure too high. One can imagine the jump from the neck to the rifling with a two diameter boolit.

I've found wheat bran filler to cover some sins in fit but I prefer wheat germ which flows easier and measures easier and raises pressure less. I have had a ring of filler left behind the neck. I'd say COW is similar to grits which I have played with. Grits raises pressure considerably. It makes for a fast load with low muzzle blast as the powder gets burned quickly with high pressure which translates into an efficient load with low muzzle pressure. I've had better results with Dacron and more powder (or not).

The trick is to launch the boolit into the bore at low pressure, that is, before the pressure has risen too much. I think the heavy fillers like COW and wheat bran resist flow so that less pressure is felt by the boolit initially.

One problem I found with the two-groove is there is so much metal displacement that the base gets distorted and in my case, unevenly. That means an appropriate boolit design would be required. My design was inappropriate for the application being solid (smooth sided). The common drive band design should be just fine but the tendency to shear is greater, putting a pressure restriction on the boolit.

[curator]

Accuracy with 2-groove barrels is also determined by the type (design) of bullet you use. Some (but not all) "bore-ride" boolits work great others not so good. Personally, I have found one diameter bullets like 311467 and the .314" LBT LFN design have been the most accurate in my 2-groove Lee Enfields. I believe .303guy has pointed out the negative consequences of base fins caused by metal displacement with the 80% land, 20% groove Lee Enfield 2-groove barrel. Fillers seem to prevent base-fins and also prevent gas-blow-by which prevents leading and leads to accuracy for subsequent shots. All of the disclaimers about fillers apply. They are only one tool in the serious cast-boolit handloaders bag 'o tricks,

[PAT303]

They are a law all to themselves,my 2 groove won't shoot any full dia boolits,only CBE 314220 and NOE 316299 bore riders.I suspect your sizing your boolits down when seating in the neck which is causing the keyholing,I use H4198 at 22grns with COW seated in unsized cases and it works well. Pat

[Bman1954]

I have been just neck sizing as to save wear and tear on the brass.I will anneal some cases and run them through the full length sizer and bump the shoulders back.They have been tight chambering so it's probably time to resize.My lyman mold was undersized when I bought it and it had to take a trip back to lyman to be opened up.I wish it was bigger but I cast with monotype so it's not too bad.

[Bman1954]

Well I went to the range with the full length resized loads with cow over 21 gr of IMR4227.The bolt was not sticky and chambering was nice.The gun will shoot 3-4 in. groups with this load and I'm a happy camper.The bore has never looked better. Craig

[1johnlb]

Tight chamber after fireforming brass in the 303 is somewhat normal. The more it fits the chamber the harder the extraction but you increase accuracy and case life, also. If it's extremly hard you may have something foreign in the chamber. Some folks, after the fireforming has been done, lightly lube the cases for assistance on extraction. 303 seals on the rim, you just have to be sure to use something that won't build up in the chamber. I have about 10 or so reloads on my cases and have NO intention of fl sizing them, they drag on extraction but I'm not volley firing or doing a mad minute, so it's good.

[303Guy]

I lightly lube my cases. I don't load to max pressure though but even with moderate loads the lube does not prevent case wall grip but it does prevent case elongation and head separations. Light lubing means one can hardly feel the lube. With excess head space the cases will sometimes remain forward with the primer backed out.

303 seals on the rim

That sounds like a typo? Normally (by design) the 303 head spaces on the rim but we reloaders like to headspace on the shoulder.

[PAT303]

If you have problems with extraction to the point of needing to oil your cases I'd seriously look at your handloading technique,303's need nothing more than the shoulder bumped when tight then neck sized,oil in the chamber will not fix any thing and will cause a very big drop in accuracy. Pat

[303Guy]

oil in the chamber will not fix any thing and will cause a very big drop in accuracy.

That's true. It will also increase bolt face thrust some.

If you have problems with extraction to the point of needing to oil your cases I'd seriously look at your handloading technique

That's true too. It could of course be caused by some irregularity in the chamber like a rusted area maybe. Or if the bolt closes with resistance it the case would be hard to extract. That's if the resistance is caused by the case body being too large. Sometimes just partial full length sizing so that the should is not touched will solve the problem but often the chamber shoulder is so far forward as to be not possible. That's where I made a body die with no shoulder. I just wish I could find it! But it's not too bad, the case taper is a standard taper reamer angle. Easy to make. or was that the hornet? Heck, I'll have to check now.